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oil pressure problem

I have a 10 ton Copeland discus and a 15 ton copelamatic on a rack system. This is a R22 system. They share a common hot gas line and suction line. The discus maintains a constant oil pressure out put at the pump of 90 pounds. The copelamatic on start up has a oil pressure output of about 85 pounds but it slowly falls and eventually trips my oil pressure control. The discus is a new compressor. The previous discus was doing the same thing. It busted one of the connector rods. The oil pump is new, I have a crank case heater on the comp and there is no foaming in the sight glass. The oil level is 1/2 way up the sight glass. I have installed a new oil separator on the system and it works great. This system is at a Save A Lot store and takes care of medium temp display boxes. It seems like there is an internal oil leak in the compressor causing the oil pressure to fall off. Has anyone encountered this problem before?

whats up with all the chillers avatars? I liked the pink donut better! chillers are the new hvac fashion!I'm a big boy working on big intimidating chillers blah blah blah if I ever get an avatar it would be a window shaker

i like this avatar because it is from a retrofit we did on a 47 year old chiller and the avatar is of the graphics on the adaptaview!
really pretty cool! old retro graphics on an old retro chiller with modern controls!

kind of abstract!

Originally Posted by valdelocc

Thats right, although there maybe gunk floating around.

whats up with all the chillers avatars? I liked the pink donut better! chillers are the new hvac fashion!I'm a big boy working on big intimidating chillers blah blah blah if I ever get an avatar it would be a window shaker

I WILL SELL WORK,GENERATE BUSINESS, GO GET NEW CUSTOMERS!
YOU SHUT THE HELL UP AND QUIT RUNNING YOUR MOUTH!

I have a 10 ton Copeland discus and a 15 ton copelamatic on a rack system. This is a R22 system. They share a common hot gas line and suction line. The discus maintains a constant oil pressure out put at the pump of 90 pounds. The copelamatic on start up has a oil pressure output of about 85 pounds but it slowly falls and eventually trips my oil pressure control. The discus is a new compressor. The previous discus was doing the same thing. It busted one of the connector rods. The oil pump is new, I have a crank case heater on the comp and there is no foaming in the sight glass. The oil level is 1/2 way up the sight glass. I have installed a new oil separator on the system and it works great. This system is at a Save A Lot store and takes care of medium temp display boxes. It seems like there is an internal oil leak in the compressor causing the oil pressure to fall off. Has anyone encountered this problem before?

Couple things.

#1. Telling us output pressure is, largely, meaningless. You need to properly measure NET oil pressure, or pump outlet pressure minus crankcase pressure. With a Copeland, that should be 50#.

Looks like a Trane Centravac Chiller. When these old chillers are running just right with no air in the system they are the quietest chiller ever.

Originally Posted by supertek65

LMAO!!!!!!!!!! ROFL!!!!!!!!!!!!!

i like this avatar because it is from a retrofit we did on a 47 year old chiller and the avatar is of the graphics on the adaptaview!
really pretty cool! old retro graphics on an old retro chiller with modern controls!

I know how to check net positive oil pressure. The pump out put pressure is the one that falls. The suction remains constant. Read the post a little closer. I said that the discus has been replaced because it was the one with the busted rod. I have pulled the oil screen and it is clean and I have changed the oil also. It is a 4D model with two heads.

Originally Posted by jpsmith1cm

Couple things.

#1. Telling us output pressure is, largely, meaningless. You need to properly measure NET oil pressure, or pump outlet pressure minus crankcase pressure. With a Copeland, that should be 50#.